中颅窝区脑外肿瘤患儿的临床及磁共振成像表现

Clinical manifestations and magnetic resonance imaging features of middle cranial fossa tumors in children

目的:分析中颅窝区脑外肿瘤患儿的临床及磁共振成像(magnetic resonance imaging,MRI)表现。方法:收集87例中颅窝区脑外肿瘤患儿病例资料,对患儿的临床表现及影像学资料进行分析。结果:本研究中肿瘤均为单发,发病率最高者为错构瘤,最低者为骨母细胞瘤。错构瘤边界光滑,平扫与脑组织信号相仿;颅咽管瘤好发于鞍区并沿组织间隙生长,蛋壳状囊壁钙化为其特征性表现;非霍奇金淋巴瘤平扫呈T1WI等或略低信号,T2WI接近脑灰质信号,扩散加权成像(diffusion-weighted imaging,DWI)则呈高信号,增强后强化较均匀;脊索瘤主要位于斜坡和蝶鞍并侵犯周围组织;脑膜瘤边界光滑,与颅底骨质呈宽基底,少见坏死,增强后明显强化;横纹肌肉瘤信号不均,边界不清伴周围溶骨性破坏,增强后强化不均;骨母细胞瘤好发于脊柱,位于颅内者罕见,瘤体呈膨胀性生长,常伴囊变坏死,瘤骨及瘤周硬化缘是其特征性表现。结论:患儿中颅窝区脑外肿瘤发生位置深,临床症状隐匿且多样化,发现时多为晚期,早期行MRI检查有助于提高临床诊断率。该类肿瘤的MRI表现具有一定特征性,但大多数肿瘤的确诊仍需依赖病理学检查。

Objective: To analyze the clinical manifestations and magnetic resonance imaging(MRI) features of middle cranial fossa tumors in children. Methods: Eighty-seven children with middle cranial fossa tumors were enrolled in this study, and the clinical manifestations and imaging data were retrospectively analyzed. Results: All the tumors of this group were single lesion. The highest morbidity of tumors in this group was hamartoma, and the lowest morbidity of tumors in this group was osteoblastoma. The border of hamartoma was smooth, and its MRI signal was similar to brain tissue. Craniopharyngioma is usually found in the sellar region and grows along the interstitial space. The characteristic feature of craniopharyngioma was the eggshell shape calcification. Non-Hodgkin’s lymphoma showed iso-and slightly hypo-intense signals on T1 WI, and its signal was close to gray matter on T2 WI, with relatively homogeneous enhancement. Diffusion-weighted imaging(DWI) shows high signal. Chordoma was usually located in the clivus and sella turcica, with invading surrounding tissue. The border of meningioma was smooth and it was closed association to skull base with broad base. The necrosis of the tumor was rare and it had obvious enhancement. The MRI signal of rhabdomyosarcoma was uneven and the border was unclear, with the surrounding osteolytic destruction. After contrast injection, heterogeneous enhancement was seen in these tumors. Osteoblastoma often occurs in the spine and is rare in the intracranial region. The tumor showed swelling growth, it usually has the tumor bone and the margin of peritumoral cirrhosis. It often accompanied by cystic degeneration and necrosis. Conclusion: The locations of middle cranial fossa tumors in children were deep, and the clinical symptoms were cryptic and diversified. Most diagnosis of the diseases were late. Early MRI examinations can help improve the clinical diagnosis. The middle cranial fossa tumors present some characteristic MRI features, but the definite diagnosis still needs the histological findings.